That was exactly was was done: same Laptop same HDD plain install of Windows 8 Direct activation with legal key via phone, kept ID in text file upgrade to WMC activate with free WMC Key followed last week by install of 8.1 activate with legal and same key a 8 upgraded to WMC try to activate with the free WMC Key not activate start phone activation and used old ID rejected start activation again gave new ID activated NO any hardware change ad or whatsoever, activation directly after installation and upgrade to WMC, NOTHING else! That computer ID MS is asking for, get changed. The Serial No. is quite hard to change. I had try that once on an Sony Laptop, it were impossible. Those Hardware UUID is hard coded.
If you compare both conditions (blue) the installation ID would be the same. IMHO. You should have used the installation ID AFTER you have upgraded /activated to WMC
Yen is correct, if your description of what you did is accurate, then you tried to use an ID from the wrong situation. You recorded the confirmation ID for a Pro (without WMC) system. You tried to reuse it on a Pro with WMC system. It's not surprising that it didn't work.
As I wrote, sometimes the next few days and if I've time, I'll change the son's computer to 81. and I'll keep both ID's because I'll need to call to MS for activation again. If my son didn't deleted the text file, the ID fropm last phone activation is still on his computer. Let see how it will be!
If on your son's PC is nothing left at all save at least the current installation ID before you do anything that you can compare it later. slmgr /dlv. If you still have both confirmation ids on your son's PC and they are different, then it is evidence that they have changed due to version change already W8-->W8 WMC! Hardware has not when upgraded windows. This means the installation ID has changed also-->would prove you have a inconsistency in your methodology already. So your son has the following condition: plain install of Windows 8 Direct activation with legal key (via phone). upgrade to WMC activate with free WMC Key Then go on: same machine same HDD install of 8.1 Apply same legal w8 retail key slmgr -ipk <key>. If you still have the original confirmation ID FROM W8 (first activation) try to apply it here. slmgr –atp <CID>. Either way, activate it. upgrade to WMC apply same free WMC key start phone activation and verify /use installation ID obtained from previous installation, or apply the confirmation ID (from previous activation WITH WMC, last phone activation on original PC) directly. slmgr –atp <last original CID>
In such a case, unless M$ specifically prevents the MAK key being used in win 8.1 at this stage, is it possible to use the confirmation id (saved from previous Win 8.0 x64 MAK key install) and activate win 8.1. If so, whether going on line will de-activate the OS. As seen from the forum, MAK can not be used to activate Win 8.1. Thanks in advance.
MAK's issued for w8 are not made to activate W8.1. But there will be new MAK's that can activate. Retail keys and MSDM keys ARE made to upgrade directly (are valid at w8.1). It has nothing to do with the confirmation ID directly, it are the MAKs which are not able to activate w8.1 (MAK's issued for w8 are not valid at w8.1). I suspect when you try to apply a confirmation ID returned from a MAK w8.0 activation on a w8.1 installation (same machine of course) it refuses to activate already. Needs to be confirmed, though.
Turns out I made a small mistake in my testing, and the part in red is not actually true. Although I used the same machine for my tests, when I installed the x64 version I increased the memory to 2 Gb, from the 1 Gb I used for the x86 version. This actually affects the Installation ID. Once I reduced the memory to 1 Gb, the x64 version generated identical Installation ID to the x32 version. In conclusion: identical Installation ID is generated by identical hardware, identical product key and identical Windows edition (Pro or WMC), irrespective of whether Windows is 8 or 8.1, or x86 or x64. I will edit the original post as well.